The present invention relates to a video cassette recorder (VCR) board. More particularly, it relates to a VCR having a preamplifier incorporated with its main circuit board. This application is based on Korean Patent Application No. 96-10610 which is incorporated by reference herein for all purposes.
FIG. 1 is a block diagram showing a general VCR. Referring to FIG. 1, when a deck portion 1 picks up a video signal recorded on a video tape (not shown) and outputs the picked up video signal, a preamplifier portion 2 amplifies the weak picked up video signal and outputs it to a video signal processing portion 3. The video signal processing portion 3 processes the video signal reproduced from the tape, and then divides it into an image signal and an audio signal, and outputs the two signals.
Additionally, when recording a TV broadcast signal, a tuner 4 selects a TV broadcast signal and the video processing portion 3 performs a signal processing of the selected TV broadcast signal. Then the preamplifier portion 2 amplifies the signal processed by processing portion 3, and the deck portion 1 records the TV broadcast signal on a video tape (not shown).
A conventional VCR has a preamplifier board which is separate from its main circuit board, as will be further described below. FIG. 2 is a perspective view showing a portion of a conventional VCR whose preamplifier board 25 is separate from its main board 26.
In FIG. 2, the video signal which is picked up from the video tape through a drum 22 in a deck 21 is output to a preamplifier board 25 through a connector cable 23. The preamplifier circuitry (not shown) is located on the preamplifier board 25 and is sealed-up in a shielding case 24 in order to prevent the weak picked up video signal from being interfered with by external noise. The video signal which is picked up by the drum 22 is output from the drum 22 to the preamplifier board 25 through the connector cable 23 and is amplified by about 60 dB. The video signal amplified in the preamplifier board 25 is output to the video signal processing portion 3 of a main circuit board 26.
The conventional preamplifier board 25 is vertically connected to the main board 26 as shown in FIG. 2. That is to say, the preamplifier board 25 is conventionally mounted on the main board 26 at a right angle, which would make the preamplifier board 25 lie in a vertical plane, assuming that the main board 26 lies in a horizontal plane. Because of this vertical mounting of the preamplifier board 25 with respect to the main board 26, the productivity of connecting the connector cable 23 between the drum 22 and the preamplifier board 25 is lowered since the inner space of a VCR set is narrowed by the preamplifier board 25. Also, since the preamplifier board 25 is vertically connected to the main board 26, it is hard to maintain a good grounding between the deck 21 and the shielding case 24, because it is difficult to obtain a wide enough contact area between the deck 21 and the shielding case 24. The result is that it is hard to obtain grounding for the shielding case 24 sufficient to remove the interference of external noise.
It is an object of the present invention to provide a VCR to improve the productivity of a VCR by incorporating a preamplifier board into the main circuit board and to remove the interference of noise by securing a wider grounding surface for a preamplifier shielding case.
To achieve the above object, there is provided a video cassette recorder (VCR) having a preamplifier incorporated with its main board. The VCR comprises a deck for picking up a video signal, a connector cable for supplying the video signal picked up by the deck to the preamplifier, a main board on which the preamplifier is incorporated, and a shielding case, contacting a portion of the deck, for shielding the preamplifier.
The shield case contacts a wider surface of the deck since it is level with the deck.